Hydraulic cushion for sheet-metal presses



April 3, 1928.. 1,664,485

, F. J. RODE HYDRAULIC cusnron FOR SHEET METAL PRESYSES Filed April 1927April 3, 192a. 1,664,485

F. J. RODE V HYDRAULIC CUSHION FOR SHEET METAL PRESSES Filed April 19274 Sheets-Sheet 3 April 3, 1928.- 1,664,485

F. J. RQDE HYDRAULIC cusnrou FOR SHEET METAL PRESSES Filed April 1927 4sheets-Sheet 3 April 3, 1928. 1,664,485

F. J. RODE HYDRAULIC CUSHION FOR SHEET METAL PRESSES' Filed April 1927 4Shae Patented Apr. 3, 1928.

UNITED STATES PATENT OFFICE.

FRIEDRICH J. BODE, OF QHICAGO, ILLINOIS, ASSIGNOB T IABQUETTB .llOOL &MFG. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 01' ILLINOIS.

mnaumc cosmos son snnnr-xn'rn. russns.

Application med April 15,1927. Serial no. 184,070.

direction by the said cushion, and one ofthe objects of the invention isto provide an improved hydraulic cushion of this character in which apredetermined quantity of liquid is used in the cushion, the cushionembodying cylinder and piston members,

the liquid being circulated from beneath p the piston .underpredetermined conditions to relieve the resistance pressure.

A further. object is to provide improved means for restoring the blankor work holder to its normal position.

To the attainment of these ends and the accomplishment of other new anduseful objects as will appear, the invention consists in the features ofnovelty in substantially the construction, combination and arrangementof the several parts hereinafter more fully described and .claimed andshown in the accompanying drawings illustrating this invention, and inwhich Figure-1 is a view partly in elevation, partly in section andpartly broken away of a single acting metal working press having anhydraulic cushion constructed 1n accordance with the principles of thisinvention applied thereto. v

Figure 2 is an enlarged detail horizontal sectional View taken on line2-2, Figure 1.

Figure 3 is an enlarged detail vertical. sectional view taken on line3-3, Figure 1.

- Figure 4 is a detail vertical sectional view taken on line 4-4, Figure2.

Figure 5 is a view similar to Figure 1, showing the cushion applied to adouble action'press.

Figure 6 is a view partly in elevation, partly in section and partlybroken away of one side ofa single acting pres, show-. ing another formof this invention. I

Figure 7 is a view similar to Figure 6'of one side of a double actingpress showing another form of the invention. 3

Referring more particularly to the drawings and to the form of theinvention shown in Figure 1, the numeral 10 designates the supportinbase or bolster plate of a sheet metal wor ing ress. The press embodiesuprights 11 having a reciprocating ram or mem er 12 operated by means oflinks 13 connected to a crank shaft 14, the latter being driven by anysuitable source of power (not shown). Connected with the ram 12 is a die15 which co-operates with a die 16 that is supported by the bed plate10. A work holding member 17 encompasses the die .16 and is supported sothat in its normal position its up er surface willbe substantially flushwit the uppersurface of the die 16, b meansof pins 18 that pass throughthe ed plate 10 and rest upon a ad or plate 19.

All of the above referred to parts are'of the ordinary and well knownconstruction. Arranged beneath the press, preferably within a pit 20 isa support 21 which is in turn supported by means'of suitable supports orhanger members 22 from any stationary part of the press.

Arranged upon the support 21 is a cylinder 23 aving a piston 24rwiprocable therein, and connected with the piston is a piston rod 25which passes throu h a suitable stufling box 26 in the end of t ecylinder. The end of the istonrod 25 contacts with the pad or plate 19and may, if

' desired, be secured thereto by means of suitable fastening devices 27.

Leading from the cylinder 23 adjacent the bottom thereof is a passa e28, which has communication with a va ve casing 29, in which a valve 30is arranged. A spring 31 is provided for holding the valve 30 seated,and means such as a screw device 32 is also provided for varying thetension of the spring 31. The valve .30 is adapted to be unseated so asto let the liquid flow from the cylinder23 out of the passage28, by theressure exerted upon the ligpi n the cylmder by the piston 24 and t e sring 31 is adjusted to produce the desi resistance pressure againstwhich it is necessary to unseat the valve 30 to open the' passage 28. Bymeans ofthe adjusting device 32 the resistance pressure. of the valve 30may. be

varied.

Leading from the valve casing 29 is a passage 33 which has communicationwith .a conduit 34, and this conduit preferably struction and operationof each of these cyl-,

- inders 36 is the same the description of one will apply e ually aswell to both.

The cylin er 36 has a piston 37 reciprocable therein, and a resllientmember 38 I such as a coil spring is provided, which tends normally tomove the piston 37 in one direction.

The spring 38 is supported preferably by means of a rod 39 that isanchored to the reciprocating ram of the press. The rod passes through asuitable stuflin box 40 in the top of the cylinder 36 and t irough thepiston 37. The spring 38 is coiled about the rod 39, one end of thespring resting against the piston 37 and the other endagalnst a washer41 carriedby a'nut 42 threaded on the lower end of the rod. The rod 39moves with the cam 12 and energy sufficient to discharge the liquid fromthe cylinder 36 will not be stored'in the spring 38 until the piston 37is moved downwardly by the admission of liquid into the top of thecylinder, as the lowering ofthe rods 39 serves to loosen or relieve thesprings of their stress. The energy of thesprings serves to'restore thepiston 37 and thereby force the liquid .out of the cylinder 36, in amanner to be described. I

Leading from the top of the cylinder 23 is a passage 43 which hascommunication with a passage 44 in the top of the cylinder 36 by meansof a conduit 45, which passage 44 is located on the side of the piston37 opposite to the side on which the spring 38 is located.

Leading also from the cylinder 36 and from the same side of the piston37 is a conduit 46 which has communication with the cylinder 23. on thepressure side of the piston24asat47: C v

A. check valve 48 is located in the conduit 46 and is arranged to openso as to allow the liquid to flow from the pressure side ofthe valve 50will close so that the liquid I will be confined. within the cylinders.

' In the form of theinv'ention shown in "Figure 5, the cushion isapplied to a double acting press and in which press the ram 12' isconnected by means of links 13 with the crank shaft 14 and carries ablank holding member 51 which co-operates with a die or blank holdingmember. 52 mounted upon the bed plate 10 of the press. A punch 53 isconnected by means of a suitable link 54 with a crank shaft 55 andreciprocates through the die or blank holder member 51. This punch 53co-operates with a vwork holding member 56 that is supported by means ofpins 57 that pass loosely through the bed plate 10 and engage and restuponthe pad or pin plate 19. f

In this form of the invention the rods '39 are connected with theblank'holding member 51 and pass loosely through the bed plate 10 sothat as the ram descends the rods 39 will be lowered and the springs 38will not be compressed until the liquldis.

.forced into thetop'of the cylinders 36 to' lower the pistons 37. Thiswill not occur until after the blank holding member 51' contacts withthe 'work to grip the work in connection'with the blank holding member52. 'This will provide a lift out for-the work at a predetermined timein the operation of the press. The pressure of the springs increasesonly slightly on the down stroke.

In these two forms of the invention the.

stress of the springs 38 will not be increased until after thecommencement of the operation of shaping the work over or with respectto the dies. y

In the form ofthe invention shown in Figure 6, the rods 39 are connectedto a stationary part of the press, such as the bed plate 10. With thisarrangement the rods 39 are at all times stationary'so that when theliquid isforced into the top of the cylinders 36 above the pistons 37,the pistons will be lowered by the pressure and the stress of thesprings 38 will be increased during the lowering movement, but thestress thus created or energy stored in the springs 38 is onlysuflicient to eject the liquid from the cylinders 36 to force the sameback into the cylinder 23 and thereby. raise the pis ton 24.

In the form of the invention shown in Figure 7the rods 39 are connectedwith another movable part of the press's'uch as the pad or pin plate 19,with the result that the rods 39 will not commenceto lower until the pador pin plate 19 is lowered through the medium of the pins 57 which willnot occur until the blank or work is being shaped by the dies. Thelowering movement of the rods 39 will not-tend to relieve any stressupon the springs 38. but the stress remains constant while the rods aredescending, as the volume of liquid in the cylinders, above .the pistonsis ,eqgal. Energy will be stored forced into the cylinders 36 by thelowering of the piston 24.

In all forms of the invention it will be manifest that there is the samevolume of displacement on the top side of the piston 24 as on the topside of the pistons 37 and this will cause the springs 38 to maintainthe same tension, with the exception of the form of the invention shownin Figure 7, and in which form the tension of the spring is increased bythe forcing ofthe liquid into the cylinders 36 due to the fact that therods 39 are maintained stationary.

In starting this cushion in operation the cylinders are first filledwith liquid and the springs 38 are then adjusted to the desired tension.The operation of all forms of the invention with respect to the returnof the pin plate or blank holding member is the same, but the operationwill be described in connection with the form of the invention shown inFigure 1.

Assuming the parts to he in the position shownin Figure 1, apredetermined quantity of liquid will be contained in the cylinder 23and the pistons 24 and 37 will be at the limit of their upward movement.

When the ram 12 descends the rods 39will be lowered and when the die 15engages the work a further lowering movement of the ram will cause theblank or work'holding "member 17 to he wfgreed downwardly. The

pins 18 will then forcethe pin-plate or pad 19 downwardly and the piston24 will be lowered in the cylinder 23, against the resistance of theliquid in the cylinder 23 and which resistance pressure may bepredetermined by adjusting the spring 31 so as to maintain'thepredetermined resistance pressure upon the valve 30 and against whichlatter pressure the valve 30 must be unseated before the liquid will beforced from the cylinder 23 by the piston 24.

When the piston 24 exerts a predetermined pressure upon'the liquid inthe cylinder 23 the valve 30 will be unseated against the stress of thespring 31 and the liquid will be forced from the cylinder 23 through thepassage 28, through the conduit 44 and into the top on the other side ofthe cylinder 23 on the side of the piston, out of the passage 43,through the conduit 45 and passage 44 into the top of the cylinder 36. A

continued movement of the piston 24 downwardly will continue to forcethe liquid from the cylinder 23 into the cylinder 36.

As the liquid flows into the cylinders 36 against the pistons 37 thepressure thus created upon the liquid by the piston 24 will cause thepistons 37 to move downwardly to store energy in the springs 38. Theenergy thus store in the springs 38 will be negligible as a resistancepressure against the resistance pressure to the piston 24.

After the piston 24 has reached the limit of its downward movement or atthe end of the stroke of the ress,the upward stroke of the press willtien commence. This will relieve the pressure upon the piston 24 andwill raise the rods 39. At this time the energy in the springs 38 willoperate upon the pistons 37 in the cylinders 36 to return these pistons.Upon the return movements of the pistons 37 the liquid in the cylinders36 will be forced from the cylinders 36, through the conduits 46. Thevalves 48 will then be unseated and the liquid will flow into thecylinder 23'on the pressure or lower side of the piston 24 and therebyraise the piston 24 to restore the pin plate or pad 19.

The pressure exerted upon the liquid by the springs 38 and pistons 37 inreturning the piston 24 is only sufiicient to restore the pin plate orpad 19.

Upon the next downward stroke of the piston 24 the liquid will be forcedback into the cylinders 36 when the resistance pressureof the valves 30has been overcome.

With this invention it will be manifest that the hydraulic pressure maybe controlled at any time during the cycle of operation of the press bythe adjustment of the resiliently yielding element or spring 31 and bysuch adjustment the degree of pressure necessary to unseat the valve 30will be controlled at will.

While the preferred form of the invention has been herein shown anddescribed, it is to be understood that various changes may be made inthe details of construction an'd'in the combination and arrangement ofthe several parts, within the scope of the. clalms, without departingfrom the spirit of this invention.

What is claimed as new is 1. A. sheet metal working machine embodying awork holding element, an hy-.

draulic cushion for resisting the movement of said element in onedirection, said cushion embodying cylinder and piston members one ofwhich is acted upon by said element, a conduit for leading the liquidfrom one side to the other side of the piston, a valve for controllingthe conduit, variable resistance pressure means acting upon the valveand against which pressure the valve is adapted to be opened by pressureupon the liquid by the movement .of the said'element, means forrestoring the work holding element, the last said means embodyingcylinder and piston members, means whereby the liquid will be forcedfrom thefirst to the second said cylinder when the said valve is opened,and means for forcing the liquid from the second said cylinder back intothe first said cylinder to thus restore the work holding element.

2'. In a sheet metal working machine a work holding element,an-hydraulic cushion for resisting the movement of said element in onedirection, said cushion embodying cylinder and iston members, a conduitfor leadin the iquid from one side to the other side the piston, a valvefor controlling the conduit, variable resistance pressure means actingupon the valve and against which pressure the valve is adapted to beopened by pressure upon the liquid bythe movement of said element, asecond cyhnder,

a conduit leading from the pressure side of' the piston in the firstsaid cylinder into the second cylinder, a valve for controlling thesecond recited conduit, and means in the second said cylinder forforcing the liquid therefrom and back into the first said cylinder at apredetermined time in the cycle of operation of the press and on thesaid pressure side of the piston therein to restore the said workholding element.

3. In a sheet metal working machine a work holding element, an hydrauliccushion for resistingthe movement of said element in one direction, saidcushion embodying cylinder and piston members, a conduit for .leadingthe liquid from one side to the other side of the piston, a valve forcontrolling the conduit, variable resistance pressure means acting uponthe valve and against which pressure the valve is adapted to be openedby pressure upon the liquid by the movement of said element, a secondcylinder, a conduitleadlng from the pressure side of the piston'in thefirst said cylinder into the second cylinder, a valve for controllingthe second recited conduit, and means in the sec-. ond said cylinderadapted to be acted upon by the entrance of liquid into the second,

cylinder for forcing the liquid from the sec-, ond cylinder back intothe first said cylinder at a predetermined time in the cycle of op?eration of the press to restore the said work holdin element; 7

4. H ydraulic-cushioning means for a sheet metal working press embodyingcylinder and piston members, one of w ich is operated upon by a workholding element, a conduit for leading the liquid from one to the otherside of the piston, a valve for con-,

trolling the conduit, variable resistance pressure means acting upon thevalve, a second cylinder, a conduit for leading the liquid from thepressure side of the piston in the first said cylinder into the secondcyla {to inder, a valve for controllin the last said conduit, a pistonin the second said cylinder, and means for moving the last said pistonin a direction to force the liquid from the second cylinder through thelast said conduit back into the first said cylinder at a predeterminedtime in the c cle of operation .of the press to restore t e work holdingelement, energy being created in the last said means by the discharge ofthe liquid into the second said cylinder from the first said 0 1inder.5. ydraullc cushlonmgmeans for a sheet means acting l metal workingpress embodyin cylinder and piston members, oneof whic is operated uponb a work holding element, a conduit for lea ing the liquid from one tothe other side of the piston, a valve for controlling 10 the conduit,variable resistance pressure upon the valve, a second cylinder, a conlit for leadin the liquid from the pressure side of the piston in thefirst said cylinder into the second cylinder, a 76 valve for controllingthe lastvsaid conduit, a piston in the second said 'cylintlerfand' resilient means for moving the last said piston in a direction to forcethe liquid-from the second said cylinder back into the first said 80cylinder at a predetermined time in the cycle of operation of the presstorestore the workholding element and against the stress of whichresilent means the liquid is forced into the second cylinder from thefirst said cylinder. 7

6. Hydraulic cushioning means for a sheet metal working press forresisting the movement of a blank holding element in one direction andembodying cylinder and piston members, one of said members beingactedupon by the said element, a second cylinder and piston, meansitendingnormally to move the; last said piston in a direction-to eject the liuidfrom the second said cylinder,

a con uit for leading the liquid from the cylinder into tflesecond-cyiiiider against the PlSilOIltherein to move the lastcsaidpiston against the-stress of the last said' means, a 10 valve. forcontrolling the said conduit, variable resistance pressuremeans actingupon the valve, a second conduit for leadin liquid from the second'saidcylinder ack into the first said cylinder to restore the m5 work holdingelement at ,a predetermined work holding element, a second cylinder and"5 piston, a conduit leadingfrom the pressure side of the piston in thefirst said cylinder to the pressure side of the piston in the second 'cyinder, variable resistance means for closing said conduit and operableby the no pressure created upon the liquid in the first sa1d cyl1nder toopen the conduit, means 'for moving the piston in the" second saidcylinder in a direction to discharge liquid therefrom and which means,is rendered active by the liquid delivered into the second cylinder, asecond conduit for leading the liquid from the pressure side of thepiston in the second cylinder to the pressure side of the piston in thefirst recited cylinder to restore the 13 pressure sideof the piston intheii r stisaid V the last said piston, and a valve for controlling thelast said conduit.

8. Hydraulic cushioiiing meansfor a sheet metal working press forresisting the movement of work holding element in one direction andembodying cylinder and piston members one of which is acted upon by thework holding element, a second cylinder and piston, a conduit leadingfrom the pressure side of the piston in the first said cylinder to thepressure side of the piston in the second cylinder, variable resistancemeans for closing said conduit am operable by the pressure created uponthe liquid in the first said cylinder to open the conduit,mechanicalmeans for moving thepiston in the second said cylinder in adirection to discharge liquid therefrom and which means is-renderedactive by the liquid delivered into the second said cylinder, means forconveying the liquid from the pressure side of the piston in the secondsaid cylinder to the pressure side of the piston in the first saidcylinder at a predetermined time in the cycle of operation of the pressto restore the first said piston, and means operating automatically tocontrol the last said means.

9. Hydraulic cushioning means for a sheet metal Working press forresisting the movement of a work holding element in one direction andfor restoring. said element, said cushion embodyin a cylinder and pistonmembers one of w ieh is operated upon by the said element, a secondcylinder and piston member, contractible and expansible means operatingupon the second recited piston and tending normally to move the latterin a direction to discharge the liquid from the second said cylinder,means embodyin a conduit for leading the liquid from t e pressure sideof the piston in the first said cylinder to the pressure side of thepiston in the second cylinder to create energy in the said expansiblemeans to render the latter active, variable resistance means forcontrolling said conduit and operable by the pressure created upon theliquid in the first said cylinder, means embodying a conduit for leadingthe liquid from the pressure side of the piston in the second saidcylinder back to the ress'ure side of the piston in the first saidcyhnder to restore the last said piston, and an automatically operatingvalve for controlling the last said conduit.

10. Hydraulic cushioning means for a sheet metal working press forresisting the movement of a work holding element in one direction andfor restoring the said element, said means embodying cylinder and pistonmembers one of which is acted upon by the said element, a secondcylinder and plston, a resilient element tending normally to relativelymove the last recited cylinder and piston in a direction to dischargethe liquid from the last said cylinder, means embodying a conduit forleading the li uid from the pressure side of the piston in t e firstcylin der to the pressure side of the piston in the second cylinder tocompress the said resilient element to render the latter active,variable resistance means for controlling the conduit, means including apassageway for leadwork holding elei'nent, an hydraulic cushion forresisting the movement of said element in one direction and embodyingcylinder and piston members, a second cylinder and piston members, aconduit for leading the liquid from the pressure side of the piston inthe first said cylinder to the pressure side of the piston in the secondsaid cylinder to move the piston in the latter, resiliently yieldingmeans for resisting the last said movement of the last said piston,variable resistance pressure means for controlling said conduit, aconduit for leading the liquid from the pressure side of the piston inthe second said cylinder back to the pressure side of the piston in thefirst recited c linder to restore the last said piston, an valvegiechanism for controlling the last said conuit.

12. In a sheet metal working machine a work holding element, anhydraulic cushion for resisting the movement of said element in onedirection and embodying cylinder and piston members, a second cylinderand piston member's, aconduit for leading the liquid from the pressureside of the piston in the first said cylinder to the pressure side ofthe piston in the second said cylinder to move the piston in the latter,resiliently yielding means for resisting the last saidmovement of thelast said piston, means connected with a movable part of the press forcontrolling the last said means, variable resistance pressure means forcontrolling said conduit, a conduit for leading the liquid from theressure side of the piston in the second sai cylinder back to thepressure side of the piston in the first recited cylinder 'to restore,the last said piston, and valve mechanism for controlling the last saidconduit.

13. In a sheet metal working machine a work holding element, anhydraulic cushion for resisting the movement/of said element in onedirection and embodying cylinder and piston members, a second cylinderand piston members, a conduit for leading the liquid from thepressureside of the piston in the first said cylinder to the pressureside of the piston in the second said cylinder to move the piston in thelatter, resiliently yielding means for resisting the last said movementof the last said piston, a member connected with a movable part of thepress and between which last said member and the last said piston thesaid resiliently yielding means is disposed, said resiliently' yieldingmeans being controlled by the movement of the said movable part in onedirection, variable resistance pressure means for controlling saidconduit, a conduit for leading the liquid from the pressure side of thepiston in the second said cylinder back to the pressure side of thepiston in the first recited cylinder to restore the last said piston,and valve mechanism for controlling the last said conduit.

14. In a sheet metal working machine a work holding element, anhydraulic cushion and piston members, a secondcylinder. and

piston members, a conduit for leading the liquid from the pressure sideof the first said piston to the pressure side of the second said pistonto move the latter, means for moving the last said piston in theopposite direction to force the liquid back to the pressure side of theother'piston to restore the latter, variable resistance pressure meansfor controlling said conduit, the first said means embodying a rod uponwhich the piston slides, a shoulder on the rod, resiliently yieldingmeans carried by the rod and abuttin the piston thereon and saidshoulder, an means anchoring the rod to a. movable part of the press.

In testimony whereof I have signed my name to this specification March,A. D. 1927.

FREDRICH J. RQDE.

